Sustainable virtual communities: suggestions from the colonial model

While virtual community research has contributed to the understanding of the virtual community sustainability, a need for a systematic model exists. In this paper, we propose a model of sustainable virtual communities based on the sustainability properties of animal colonies in nature. The premise of our model is that if we manage to replicate the sustainability properties of colonial systems in virtual communities, they can become longer lasting. We also present the results of an exploratory case study. The study shows that colonial properties form a construct that predicts member perceptions of their community being sustainable. While our primary objective is the conceptual introduction of the colonial principles of sustainability, the case study provides some early indications that these principles may help design systems that can bind virtual communities more permanently.

虚拟实体对象建模语言SCPL

本文给出一种新的虚拟实体对象建模语言ＳＣＰＬ。这种语言以基于控制论的行为模型ＳＣＰ为中心组织虚拟实体对象的建模,具有实现连连续和更复杂行为的能力,适用领域广。     

Living in the Hutt Space: Immersive process in the Star Wars Role-Play community of Second Life

Immersive virtual settings are evolving to become new “spaces of life”. Humans inhabit these different virtual worlds through their avatars, and tend to gather into communities. However, the behavioral factors underlying the cognitive process of immersion in virtual worlds are still far to be understood. We here investigated these factors using the Star Wars Role-Play community of the virtual setting of Second Life as a model. More specifically, our studies focused on the immersion process in the “Hutt Space”, a portion of the Star Wars Galaxy ruled by the alien species of the Hutts, which combines the trademark aspects of Star Wars universe. Using both quantitative and qualitative methods, we identified some of the factors which favor the immersion process. Our results suggest that the different behavioral factors contributing to the immersion process can be organized in three structuring dimensions: commitment, cohesion, and coherence. We also unveil a compensatory mechanism between appearance and behavioral factors in creation and maintenance of social groups in virtual worlds. Finally, we point out some of the behavioral aspects of the evolution from passive media engagement (spectators), to active media engagement (actors), and suggest a theoretical framework to investigate how human inhabit immersive virtual spaces.     

Fast continuous collision detection and handling for desktop virtual prototyping

This paper presents an overview of our recent work on continuous collision detection methods and constraints handling for rigid polyhedral objects. We demonstrate that continuous collision detection algorithms are practical in interactive dynamics simulation of complex polyhedral rigid bodies and show how continuous collision detection and efficient constraint-based dynamics algorithms allow us to perform various virtual prototyping tasks intuitively, precisely and robustly on commodity desktop computers. Especially, we present two applications of our system to actual industrial cases. We note that both tasks are performed with a simple 2D mouse on a high-end computer.     

Dedicated workspaces: Faster resumption times and reduced cognitive load in sequential multitasking

Studies show that virtual desktops have become a widespread approach to window management within desktop environments. However, despite their success, there is no experimental evidence of their effect on multitasking. In this paper, we present an experimental study incorporating 16 participants in which a traditional Windows 7 environment is compared to one augmented by virtual desktops. Within the experimental condition, each virtual desktop acts as a dedicated workspace devoted to an independent goal-oriented task, as opposed to the control condition where only one single workspace is available to perform the same tasks. Results show that adopting virtual desktops as dedicated workspaces allows for faster task resumption (10 s faster on average) and reduced cognitive load during sequential multitasking. Within our experiment the majority of users already benefited from using dedicated workspaces after three switches to a previously suspended task, as the time lost on setting up workspaces was compensated for by faster subsequent task resumption. These results provide a strong argument for supporting goal-oriented dedicated workspaces within desktop environments.     

Mapping virtual communities by their visual productions: The example of the Second Life Steampunk community

In the digital age, the identities and structures of virtual communities develop outside the traditional definitions of geography and physical constraints. Among the best models to study the identification process in virtual communities are the communities of fans of imaginary universes. Steampunk—neo-Victorian fiction with a science fiction twist—has for instance given rise to a large community, which is very active both in real life and in virtual spaces, for instance in the online 3D immersive platform Second Life. By collecting and analysing hundreds of visual artifacts generated by members of the steampunk community of Second Life, we found a repertoire of visual and lexical characteristics with which to identify the community. In addition, examining the characteristics displayed by visual productions from other communities allowed us to map relationships between different communities based on their aesthetics. This data suggests that the quantification of visual clues points out to interlocking relationships between different community aesthetics, forming a network where differences are visible, but fluidity still dominates. Furthermore, our results could serve as a model to study how communities in different media (immersive universes, games, social media based on visual materials such as Pinterest or Instagram) generate their own visual identity.     

Daonity – Grid security from two levels of virtualization

The service oriented architecture of grid computing has been thoughtfully engineered to achieve a service level virtualization: not only should a grid be a virtual machine (also known as a virtual organization, VO) of unbounded computational power and storage capacity, but also should the virtual machine be serviceable in all circumstances independent from serviceability of any of its component. At present, a grid VO as a result of service level virtualization only is more or less confined to participants from scientific computing communities, i.e., can have a limited scale. It is widely agreed that for a grid to pool resources of truly unbounded scale, commercial enterprises and in particular server-abundant financial institutions, should also “go for the grid,” i.e., open up their servers for being used by grid VO constructions. We believed that it is today's inadequate strength of the grid security practice that is the major hurdle to prevent commercial organizations from serving and participating the grid.This article presents the work of Daonity which is our attempt to strengthening grid security. We identify that a security service which we name behavior conformity be desirable for grid computing. Behavior conformity for grid computing is an assurance that ad hoc related principals (users, platforms or instruments) forming a grid VO must each act in conformity with the rules for the VO constitution. We apply trusted computing technologies to achieve two levels of virtualization: resource virtualization and platform virtualization. The former is about behavior conformity in a grid VO and the latter, that in an operating system. With these two levels of virtualization working together it is possible to build a grid of truly unbounded scale by VO including servers from commercial organizations.     

Pattern-based e-service modelling for virtual service enterprises

Business services are customisable, interactive processes that providers have the potential to carry out together with clients that benefit from the effects. It is understood that business service transactions are best organised by means of virtual networks, where information technology allows for configuring multiple providers and processes on a per-request basis. Existing conceptual models for virtual service enterprises (VSEs) propose business service virtualisation for flexible and agile regulation and control of coordination between multiple providers and clients. In this paper, we present an approach for realising business service virtualisation based on software service technology. In particular, we propose a service-oriented software architecture for representing virtual business service processes as e-services. E-service models specify flexible business service interactions between multiple providers and clients of virtual service enterprises and allow for regulation and enforcement of their coordination. We demonstrate the utilisation of our e-service SOA in the context of an e-science scenario, where we show how to design e-service models for the use case of virtual polymorph prediction laboratories.     

Upward influence tactics through technology-mediated communication tools

The globalization of work within organizations has generated a greater need for all types of workers to exert interpersonal influence through technology-mediated communication tools. This paper sheds light on the interpersonal relations process in virtual environments from the specific perspective of the choice of upward influence (UI) tactics. We suggest that virtual work settings may impact the UI tactic selected, as well as the communication medium used to enact it. In particular, we study whether the types of UI strategies found in physical environments are relevant in virtual work contexts. This research also analyzes the UI process in virtual work settings, as well as the role of communication media in that process. Results based on the qualitative analysis of the content of 14 interviews suggest that there is an influence tactic specific to virtual work relations. That tactic might be called intermediation and consists of finding an intermediary who is well connected to the target and can help define the best approach for the agent. In addition, workers often split their influence attempts into a two-step strategy in order to achieve better results, taking advantage of the capabilities of the media available for that purpose.     

Motor planning: An architecture for specifying and controlling the behaviour of virtual actors

As virtual worlds become increasingly complex, task level interaction with virtual actors becomes correspondingly important. The control problem simply becomes unmanageable if we try to interact with synthetic agents at the wrong level of abstraction. However, it is not sufficient merely to implement a set of behaviours for a virtual actor; we require some mechanism for selecting and sequencing motor skills appropriate to the current behavioural goals and the states of other objects and actors in the virtual environment. In this paper we will describe a mechanism for linking perception and action to generate routine behaviours in a process we call motor planning. We present our implementation of the skill network, in which motor skills are the nodes and the arcs represent inhibitory and excitatory connections, including extensions to this architecture based on recent work in robotics. We characterize the domain of motor planning, i.e. what kinds of behaviour can it account for, and when will it fail? We close with a discussion of the limits of our current implementation and work that remains to be done.     

Occlusion in collaborative augmented environments

Augmented environments superimpose computer enhancements on the real world. Such augmented environments are well suited for collaboration of multiple users. To improve the quality and consistency of the augmentation the occlusion of real objects by computer-generated objects and vice versa has to be implemented. We present methods how this can be done for a tracked user's body and other real objects and how irritating artifacts due to misalignments can be reduced. Our method is based on simulating the occlusion of virtual objects by a representation of the user modeled as kinematic chains of articulated solids. Smoothing the border between virtual world and occluding real reduces registration and modeling errors of this model. Finally, an implementation in our augmented environment and the resulting improvements are presented.     

Virtual goods,real goals: Exploring means-end goal structures of consumers in social virtual worlds

The aim of this study is to understand consumer goals for virtual consumption in social virtual worlds. Using a means-end chain approach, interviews with 93 users were analyzed to produce a hierarchical goal map, revealing that virtual consumption enables a diversity of goals beyond the previously identified experiential goals. The article's theoretical contributions include: (1) extending our understanding of user goals/goal relationships for virtual activities and (2) developing virtual liminoid theory, which describes transitions between users’ real-world and virtual identities and virtual consumption as a transition catalyst. The study illustrates the value of a goal focus for future research on user behavior in virtual worlds.     

The change in user and IT dynamics: Blogs as IT-enabled virtual self-presentation

Using the blogosphere as an enabling IT environment, this paper investigates how self-concept influences virtual self-presentation behavior and the use of IT artifacts. Self-presentation theory is adapted from the social psychology literature to develop a theoretical research model of virtual self-presentation. We tested the research model and hypotheses with data collected from 312 bloggers. Structural equation analysis of this data reveals a nomological net of self-concept leading to IT-enabled virtual self-presentation and the use of IT artifacts. Our findings provide a new perspective of users as heterogeneous individuals who have various self-concepts that change the sequence and dynamics among users, IT artifacts, and tasks. In contrast to traditional systems, in the social context of virtual self-presentation, users are the primary and essential drivers who determine vaguely defined tasks and systems.     

Semiotics of virtual reality as a communication process

ABSTRACT

The experience of immersive virtual reality (VR) can be considered as a communication process between human beings, mediated by computer systems, which uses visualisation and other sensory stimulation. In this paper, we analyse how VR characteristics can be explored using semiotic theory and, with methods of generative semiotics, we explore aspects of narrative and interaction in VR. We propose a semiotic analysis of VR communication focusing on syntax, semantics and pragmatics and considering also some principles of generative semiotics. The syntactic level is analysed as determined by the characteristics of the visual communication adopted. The semantic of VR is related to the functional model chosen to realise the virtual system. The pragmatic of VR is based on the human–computer interaction that changes the user's role. We explore how these aspects can be characterised in the context of VR communication design and what principles can be adopted for a VR application, and we present an analysis and a classification of the iconic signs that are being used in VR. Moreover, we present a framework that can be used to classify and describe different kinds of virtual reality systems and to better understand communication in VR, and we use it to classify eight popular systems for e-learning and collaboration.     

My hands? Importance of personalised virtual hands in a neurorehabilitation scenario

We have developed a novel and affordable way to texture virtual hands from individually taken photographs and integrated the virtual hands into a mixed reality neurorehabilitation system. This mixed reality system allows for serious game play with mirrored and non-mirrored hands, designed for patients with unilateral motor impairments. Before we can ethically have patients use the system, we must show that embodiment can be achieved for healthy users. We compare our approach’s results to previous work in the field and present a study with 48 healthy (non-clinical) participants targeting visual fidelity and self-location. We show that embodiment can be achieved for mirrored and non-mirrored hand representations and that the higher realism of virtual hands achieved by our texturing approach alters perceived embodiment. We further evaluate whether using virtual hands resized to the individual’s hand size affects embodiment. We present a 16-participant study where we could not find a significant difference with personal resized hands. In addition to rehabilitation contexts, our findings have implications for the design and development of applications where embodiment is of high importance, such as surgical training and remote collaboration.

     

Inside looking out camera pose estimation for virtual studio

This paper studies the inside looking out camera pose estimation for the virtual studio. The camera pose estimation process, the process of estimating a camera’s extrinsic parameters, is based on closed-form geometrical approaches which use the benefit of simple corner detection of 3D cubic-like virtual studio landmarks. We first look at the effective parameters of the camera pose estimation process for the virtual studio. Our studies include all characteristic landmark parameters like landmark lengths, landmark corner angles and their installation position errors and some camera parameters like lens focal length and CCD resolution. Through computer simulation we investigate and analyze all these parameters’ efficiency in camera extrinsic parameters, including camera rotation and position matrixes. Based on this work, we found that the camera translation vector is affected more than other camera extrinsic parameters because of the noise of effective camera pose estimation parameters. Therefore, we present a novel iterative geometrical noise cancellation method for the closed-form camera pose estimation process. This is based on the collinearity theory that reduces the estimation error of the camera translation vector, which plays a major role in camera extrinsic parameters estimation errors. To validate our method, we test it in a complete virtual studio simulation. Our simulation results show that they are in the same order as those of some commercial systems, such as the BBC and InterSense IS-1200 VisTracker.     

A real-time network simulation infrastructure based on OpenVPN

We present an open and flexible software infrastructure that embeds physical hosts in a simulated network. In real-time network simulation, where real-world implementations of distributed applications and network services can run together with the network simulator that operates in real-time, real network packets are injected into the simulation system and subject to the simulated network conditions computed as a result of both real and virtual traffic traversing the network and competing for network resources. Our real-time simulation infrastructure has been implemented based on Open Virtual Private Network (OpenVPN), modified and customized to bridges traffic between the physical hosts and the simulated network. We identify the performance advantages and limitations of our approach via a set of experiments. We also present two interesting application scenarios to show the capabilities of the real-time simulation infrastructure.     

Novel methods for virtual network composition

Network virtualization has been proposed as a technology that aims to solve the Internet ossification. Central to the network virtualization is a virtual network composition mechanism providing an efficient mapping of virtual nodes and links onto appropriate physical resources in the network infrastructure.This paper proposes a novel backtracking heuristic algorithm for virtual network composition. Based on this algorithm, two approaches with two different objectives are presented. The first approach (Backtracking-CR) aims to compose a virtual network using the least amount of network resources, while the second (Backtracking-LB) applies load balancing for virtual network composition. Furthermore, a linear programming approach that optimizes the virtual network composition with an objective of using the least amount of network resources is presented and used to bench mark the heuristic algorithm. Simulation results show that using less network resources by applying linear programming or Backtracking-CR does not produce higher number of successfully mapped virtual networks when is compared to load balancing approach. Results also show that the proposed heuristic algorithm is scalable to large physical and virtual networks with respect to the computation time.     

Some aspects of dynamic 3D representation and control of industrial processes via the Internet

In our research we examine and use 3D representation of industrial processes, for example the novel methods of Incremental Sheet Forming. We also test 3D imaging methods on our industrial robot solving the Rubik's Cube. We have created 3D models of our robots and their environment in our laboratory to examine the behavior of different industrial processes both in the real, and in the 3D virtual environment. We have connected the 3D model with the real system with which we could extend the features of our robots with some services that exits in the virtual space. We have also established synchronized connections of the real and virtual systems, which enables us to control the real robots and machines from its 3D model via the Internet.